Biochar-Based Integrated Nutrient Management Improves Soil Quality and Biological Functioning in a Rice–Wheat Cropping System

The key limitation to crop productivity in Punjab is nutrient imbalance and declining soil fertility, with intensive rice–wheat cropping systems and the removal of above-ground biomass after harvest negatively affecting soil health. Although mineral fertilizers have played a crucial role in achieving food self-sufficiency, maintaining long-term productivity requires sustaining adequate levels of soil organic matter to support physical, chemical, and biological soil processes. In this context, the application of amendments derived from agricultural biomass, such as biochar, can be considered a viable option for enhancing soil fertility and sustainability. The objective of the present study was to evaluate the impact of rice straw biochar combined with organic and inorganic fertilizers on the physico-chemical and biological properties of soil under a rice–wheat cropping system. The field experiment was conducted at the Department of Agronomy, Crop Research Centre, Lovely Professional University, Phagwara, using a randomized block design with nine treatments and three replications. Rice straw biochar was applied at recommended rates alongside fertilizers and organic amendments. The results indicated that biochar-amended plots exhibited higher soil pH, porosity, bulk density, nutrient availability, soil enzymatic activities, and organic carbon content than the control and sole RDF treatments. Biochar application reduced soil bulk density, increased organic carbon content, regulated soil pH, and enhanced enzymatic activity, indicating improved soil biological functioning. The integration of rice straw biochar with organic and inorganic nutrient sources—particularly 50% RDF combined with poultry manure or farmyard manure and biochar—has emerged as a promising, farmer-viable approach for improving soil quality and achieving sustainable productivity in the rice–wheat cropping system. The significance of the proposed study is placed in the context of sustainable development, as it aims to meet SDG-2 (Zero Hunger) by enhancing soil fertility and crop yields, SDG-12 (Responsible Consumption and Production) by recycling rice straw into biochar, SDG-13 (Climate Action) by improving the efficiency of soil carbon sequestration, and finally SDG-15 (Life on Land) by improving the health of the soil. The proposed biochar-based approach offers a sustainable alternative to fertilizer-intensive practices prevalent in the Indo-Gangetic Plains.